Marine Gen. John Kelly, commander of U.S. Southern Command, speaks to members of Congress at the U.S. Capitol on Wednesday. (Rob Curtis / Staff)

Army Gen. Charles H. Jacoby Jr., head of U.S. Northern Command, said once drugs reach North America, the fight to intercept them becomes much more difficult and violent. (Rob Curtis / Staff)

Tons more cocaine, heroin and other drugs could be crossing the border into the United States each year because budget shortfalls have forced the military to scale back interdiction efforts, top generals told lawmakers on Tuesday.

Marine Gen. John Kelly and Army Gen. Charles Jacoby, commanders of U.S. Southern and Northern commands, respectively, told members of the House Armed Services Committee that there has been a steady decline in interdiction over the past several years. For example, SOUTHCOM has intercepted 40 less tons of cocaine, heroin and other drugs, than it did in 2011, Kelly said during the hearing on the posture of the two commands.

“Force allocation cuts by the services are taking their toll on operational results,” he said. “In 2013, Operation Martillo disrupted 132 metric tons of cocaine, compared with 152 metric tons of cocaine in 2012, due to limited assets.”

Operation Martillo, or Hammer, is a joint U.S., European, Canadian and Latin American effort to target trafficking routes in the coastal waters along either side of the Central American isthmus. U.S. military participation is led by Joint Interagency Task Force South, a component of U.S. Southern Command.

Both Kelly and Jacoby stressed the importance of intercepting drugs before they reach the border because of the efficient, systematic operations of the drug trade.

“Once it’s in, it’s just part of this distribution network, and it’s so much harder to touch,” Kelly said.

Carrying out the drug-interdiction mission doesn’t require huge aircraft carriers, Kelly said. But they do need more ships that can carry helicopters, he said, adding that he’d like to see 16 in the fleet.

Interdiction at sea allows SOUTHCOM to seize drugs with minimal violence, he said. Military forces stop a ship, board it and take the drugs. They’re also able to gain intelligence from the drug traffickers they capture, he said.

Once the the drugs reach North America, the fight to intercept them becomes much more violent. They are also far less likely to be found in bulk at that point because they are broken into smaller packages for distrubution, Jacoby said.

Because of the advantages of interdiction at sea, SOUTHCOM has intercepted 100 more tons of drugs than the agencies working along the U.S. border, Kelly said.

“We spend 1.5 percent of the counter-narcotics budget,” Kelly said. “We get it at two to five tons at a time, without any violence. ... At best case at the borders, they’ll get 30 tons [total] with more violence.”

Jacoby said military forces need to put pressure on the cartels and other trafficking organizations. The groups are smart, efficient and already showing signs of diversifying by transporting illegal immigrants, sex slaves and resources like rare woods and minerals, Kelly said.

“This network that brings things to the United States is incredibly efficient — more efficient than FedEx could ever hope to be,” he said.

Working on these efforts with partner nations continues to be an important function of both commands. U.S. troops are working with their counterparts in Mexico, Guatemala and Honduras. Those programs are imperative and must have continued funding, the generals said.

Keeping faith with those countries, which are on the front lines of a war, requires the U.S. to show it isabsolutely committed to the fight against the illegal drug trade, Kelly said. Americans’ appetite for drugs has led to incredible levels of violence in many countries, he said. The move to decriminalize or legalize some of the drugs that he’s asking partner nations to stop — at the risk of lives and treasure — has created tension.

“The fact that they see us turning away on the drug fight makes them wonder why they shouldn’t just step back and watch it flow,” Kelly said. “It’s hard for me to look them in the eye and say we need to stay shoulder-to-shoulder on this.”